We weren't
concerned with usage of nomogram in
practice or correlation of measurements and reality. We present here a numeric
solution of equation, with usage of PC and MS Excel. We used
Newton's method with
more complicated founding of zero approximation to get the
solution.

There was written
a lot about this problem; we based our calculation on these equations:
below 23°C and
above 23°C (we
don't know the author or the source).